The elevation may be increased beyond that at which the gun can come in without its muzzle striking the upper sill of the port, by placing the edge of an inclined plane beneath the after axletree, so that in the recoil of the gun the hinder part of the carriage being forced up the inclined plane, the muzzle is thereby depressed, and comes in without striking.

364. The elevating screw is coming rapidly into use in the French naval service for all natures of ordnance : by its means the gun is easily elevated or depressed by one man, whereas the adjustment by means of the coin requires two handspike-men per gun; and in this way the elevation is effected by jerks, whereas with the screw the movement is uniform and gradual. When great changes of elevation are required, it is true that there is some loss of time by the slow process of the screw, and for this and other reasons it is objected to in our service; but a great advantage of the screw, particularly in rapid firing, is, that by the very ingenious mode of preventing the screw from turning, the elevation of the gun is not altered by the firing; whereas, in the other mode of adjustment, the coins are displaced by the shock of the discharge, so that after being fired the gun has to be restored to its previous position, the distance and charge being supposed to remain the same.

The following Table contains the extreme elevations and depressions of guns, which can be given, without injuring the ports, on each deck of different ships of war in the British navy:

365. Although for extreme elevations and depressions the inclined planes may be used, yet it must be observed that, beyond the elevation which the ports admit, the sight can no longer be taken by the tangent scale, nor by any other top-sight. A gun can then only be laid by lowering the breech to an extent regulated by a wooden graduated scale, of which one end is placed

a The toggle, and tripping-line, which we describe for the information of the general reader, is an expedient by means of which a greater degree of depression may be given to a gun than the height of the lower port-sill admits, without being struck by the muzzle of the gun in its recoil, as in fighting the weather-side in strong breezes. This is effected by placing a wooden pin (toggle) vertically under the breech of the gun, and having one end of a tripping-line fastened to the centre of the toggle, and the other end tied to the breechingbolt in the side of the ship, so that at the commencement of the recoil the toggle is tripped from its place, when, by the preponderance of the breech, the muzzle is raised sufficiently to come in clear of the port-sill.

upon the carriage, and the elevation is determined relatively with a mark or quarter-sight on the base-ring of the gun in the horizontal plane passing through its axis. Graduated coins are found to answer extremely well, and are more readily used.

366. The following rules for concentrating, or directing the fire of several guns towards a given point, are extracted from the practice of the "Excellent:"

"In concentrating any number of guns on one point at a given distance, the directions are always taken from one particular gun. If the given point is on the beam, the midship gun is taken as a guide to direct the rest; if on the bow, the after gun, and, if on the

a DIMENSIONS of the Ports, in English measures, for different natures of Ordnance, on board of French Ships of War.

Since this article was written the author has received a very interesting publication, entitled, 'Remarks on the Means of Directing the Fire of Ships' Broadsides in Converging Directions,' by Commander Arthur Jerningham, of the Royal Navy, and to which the reader is referred for his able and elaborate propositions, into which the author regrets he has not space to enter.

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quarter, the foremost gun may be used for that purpose; but as bow and quarter concentration is only intended for chasing and being chased, it is proposed to use the midship gun as the director in each case, because its training is generally equal both forward and aft, and the subject will be rendered more simple. If this method be adopted, the midship gun will be used in the three following positions:- Right-a-beam,' Extreme trained aft,' Extreme trained forward.' Concentration should not be attempted for distances beyond 400 yards, nor when there is much heel: it might be very useful in close broadside action, if an opponent were obscured by smoke, on the lower deck, but could be seen from the upper deck; for then a sight or picket over the gun concentrated on would give the line of direction, and pendulums for each division of the guns below would mark the time for firing, i. e. when the ship was upright; or it may be obtained by the clever instruments invented by Commanders Jerningham and Moorsom, each having a bar with two sight-vanes, one of which is a tangent sight, traversing on a graduated sweep, the guns below being trained and elevated to the same angles, and fired by signals from the deck, by checking lines, on tubes fitted for conveying orders from the quarter-deck to the decks below.”

367. When a vessel heels much, or there is any motion, the concentrated fire of a ship's batteries must be given simultaneously in broadsides, or by divisions, either of which methods is objectionable, and should be avoided as much as possible. Firing by volleys, in the naval service in particular, is extremely objectionable, and is rarely as efficacious as the independent and deliberate firing of one or two well-directed and well-served

guns.

Perhaps, as stated in Colonel Stevens's interesting pamphlet," it may be doubted whether the somewhat

See Answer to Question No. 103, page 192: Questions on Naval Gunnery, "Excellent."

b It was stated, by more than one eye-witness, in several public prints published at the time, that the Christian the Eighth fired by salvos of broadsides, or by divisions of guns, and that these salvos, as indeed evidently was the case, mostly missed the battery, taking effect on or at the base of the redoubt to the eastward. The author is informed that the mode pursued was to fire the salvos by a single word of command, as volleys of infantry were formerly in the British service. Thus the moment to fire was not confided to the captain of each gun, its proper director.

In reflecting on the failure of these salvos, the author regards it as a useful warning against the practice of discharging whole broadsides, or divisions of guns, at a given instant, by a word or signal of command, which fatally in

complicated system of concentration may not be carried too far, and whether it is likely to prove as efficient as the independent and quick firing of guns conducted in the ordinary manner. The moral, as well as the material, effect would probably be greater if the same number of guns were fired independently, according to the skill and judgment of well-trained captains of guns, who, each seizing the favourable moment, might spread destruction throughout the enemy's ship.

368. Naval officers and gunners should be well skilled in every available expedient for immediate substitution in all the uncertain and contingent operations of gunnery on service; it may therefore be useful to explain a method of obtaining the elevation required for striking a ship at a given distance, which may be easily practised should other means fail, as by the breaking, or want of a tangent scale, or some other contingency, and which may, moreover, be generally useful.

The method of pointing ordnance by tangent-practice, in the manner to be explained, was suggested to the author by Sir Philip Broke; and it forms the basis of the French principle for regulating elevation, which, however, by a complicated use of the line-of-metal sight, is extremely objectionable.

The elevation given to a piece of ordnance, at any range beyond point-blank, is intended to allow for the space through which the projectile falls by the action of gravity in the time of flight. Now the vertical space through which the projected body, in its flight, descends below the line of aim, is equal to the tangent of the angle of elevation multiplied by the range or horizontal distance of the object from the gun. Thus, suppose a gun to be at A, at a known height A A above

terferes with the perception of the British seaman, instructed as he now is in the use of the sights with which his gun is equipped.

To the captain of the gun should be confided the important trust of the trigger-line, and with it the duty to fire when, his eye being brought down to the horizontal plane of the sights, he judges that they coincide with the object.-Account of the Destruction of the Danish Ship of the Line Christian VIII., by Colonel Stevens, Royal Marines,